"""
Sdílený Mongo writer pro IWRS importy.

Databáze: studie
Hlavní kolekce (upsert = aktuální stav):
  iwrs_imports, iwrs_subject_summary, iwrs_visits, iwrs_notifications,
  iwrs_shipments, iwrs_shipment_items, iwrs_inventory, iwrs_destruction

Snapshot kolekce (append-only s import_id):
  iwrs_subject_summary_snapshots, iwrs_visits_snapshots,
  iwrs_shipments_snapshots, iwrs_shipment_items_snapshots,
  iwrs_inventory_snapshots
"""

import datetime
import numpy as np
import pandas as pd
from pymongo import MongoClient, ASCENDING

MONGO_URI = "mongodb://192.168.1.76:27017"
MONGO_DB = "studie"

# ── type converters (sdílené napříč importéry) ──────────────────────────────

def _py(val):
    if isinstance(val, np.generic):
        return val.item()
    return val


def to_str(val):
    val = _py(val)
    if val is None:
        return None
    if isinstance(val, float) and (val != val):
        return None
    s = str(val).strip()
    return None if s.lower() in ("nan", "nat", "none", "") else s


def to_int(val):
    val = _py(val)
    try:
        v = float(val)
        return None if (v != v) else int(v)
    except (TypeError, ValueError):
        return None


def to_float(val):
    val = _py(val)
    try:
        v = float(val)
        return None if (v != v) else float(v)
    except (TypeError, ValueError):
        return None


def to_date(val):
    """Vrací datetime (00:00:00) — Mongo nemá samostatný DATE typ."""
    val = _py(val)
    if val is None:
        return None
    if isinstance(val, float) and (val != val):
        return None
    try:
        if pd.isna(val):
            return None
    except (TypeError, ValueError):
        pass
    if isinstance(val, pd.Timestamp):
        return None if pd.isna(val) else datetime.datetime(val.year, val.month, val.day)
    if isinstance(val, datetime.datetime):
        return datetime.datetime(val.year, val.month, val.day)
    if isinstance(val, datetime.date):
        return datetime.datetime(val.year, val.month, val.day)
    s = str(val).strip()
    if not s or s.lower() in ("nat", "nan", "none", ""):
        return None
    for fmt in ("%Y-%m-%d", "%d-%b-%Y", "%d-%m-%Y", "%Y-%m-%d %H:%M:%S"):
        try:
            d = datetime.datetime.strptime(s, fmt)
            return datetime.datetime(d.year, d.month, d.day)
        except ValueError:
            pass
    return None


# ── connection / indexy ──────────────────────────────────────────────────────

_client = None


def get_db():
    global _client
    if _client is None:
        _client = MongoClient(MONGO_URI, serverSelectionTimeoutMS=5000)
    return _client[MONGO_DB]


def ensure_indexes():
    db = get_db()
    db.iwrs_subject_summary.create_index([("study", ASCENDING), ("subject", ASCENDING)])
    db.iwrs_subject_summary.create_index([("study", ASCENDING), ("site", ASCENDING)])
    db.iwrs_subject_summary.create_index([("irt_subject_status", ASCENDING)])

    db.iwrs_visits.create_index([("study", ASCENDING), ("subject", ASCENDING)])
    db.iwrs_visits.create_index([("study", ASCENDING), ("scheduled_date", ASCENDING)])

    db.iwrs_notifications.create_index([("study", ASCENDING), ("subject", ASCENDING)])
    db.iwrs_notifications.create_index([("study", ASCENDING), ("title", ASCENDING)])
    db.iwrs_notifications.create_index([("actual_date", ASCENDING)])

    db.iwrs_shipments.create_index([("study", ASCENDING)])
    db.iwrs_shipments.create_index([("status", ASCENDING)])
    db.iwrs_shipments.create_index([("shipped_date", ASCENDING)])

    db.iwrs_shipment_items.create_index([("shipment_id", ASCENDING)])
    db.iwrs_shipment_items.create_index([("medication_id", ASCENDING)])
    db.iwrs_shipment_items.create_index([("packaged_lot_no", ASCENDING)])

    db.iwrs_inventory.create_index([("study", ASCENDING), ("site", ASCENDING)])
    db.iwrs_inventory.create_index([("medication_id", ASCENDING)])
    db.iwrs_inventory.create_index([("expiration_date", ASCENDING)])

    db.iwrs_destruction.create_index([("study", ASCENDING), ("basket_id", ASCENDING)])
    db.iwrs_destruction.create_index([("medication_id", ASCENDING)])

    # snapshot kolekce mají import_id index
    for snap in [
        "iwrs_subject_summary_snapshots",
        "iwrs_visits_snapshots",
        "iwrs_shipments_snapshots",
        "iwrs_shipment_items_snapshots",
        "iwrs_inventory_snapshots",
    ]:
        db[snap].create_index([("import_id", ASCENDING)])
        db[snap].create_index([("study", ASCENDING)])


# ── import log ───────────────────────────────────────────────────────────────

def log_import(study, source_file, report_type, counts=None):
    """Zapíše záznam o běhu importu. Vrátí import_id (int sekvenční)."""
    db = get_db()
    # sekvenční import_id (max + 1)
    last = db.iwrs_imports.find_one(sort=[("import_id", -1)])
    next_id = (last["import_id"] + 1) if last else 1
    doc = {
        "import_id": next_id,
        "study": study,
        "imported_at": datetime.datetime.now(),
        "source_file": source_file,
        "report_type": report_type,
        "counts": counts or {},
    }
    db.iwrs_imports.insert_one(doc)
    return next_id


# ── upsert + snapshot ────────────────────────────────────────────────────────

def upsert_with_snapshot(collection, snapshot_collection, doc, import_id):
    """Upsertne dokument do hlavní kolekce + zapíše snapshot.

    `doc` musí mít `_id`. Hlavní dokument dostane last_import_id/last_imported_at,
    snapshot kopii s import_id a originálním _id přesunutým do natural_id.
    """
    db = get_db()
    now = datetime.datetime.now()
    main_doc = dict(doc)
    main_doc["last_import_id"] = import_id
    main_doc["last_imported_at"] = now
    db[collection].replace_one({"_id": doc["_id"]}, main_doc, upsert=True)

    snap = dict(doc)
    snap["natural_id"] = snap.pop("_id")
    snap["import_id"] = import_id
    snap["imported_at"] = now
    db[snapshot_collection].insert_one(snap)


def upsert_only(collection, doc, import_id=None):
    """Upsert bez snapshotu (pro immutable kolekce: notifications, destruction)."""
    db = get_db()
    main_doc = dict(doc)
    if import_id is not None:
        main_doc["last_import_id"] = import_id
    main_doc["last_imported_at"] = datetime.datetime.now()
    db[collection].replace_one({"_id": doc["_id"]}, main_doc, upsert=True)


def bulk_upsert_with_snapshot(collection, snapshot_collection, docs, import_id):
    """Hromadný upsert pro výkon."""
    if not docs:
        return 0
    db = get_db()
    now = datetime.datetime.now()
    from pymongo import ReplaceOne

    main_ops = []
    snap_docs = []
    for doc in docs:
        main = dict(doc)
        main["last_import_id"] = import_id
        main["last_imported_at"] = now
        main_ops.append(ReplaceOne({"_id": doc["_id"]}, main, upsert=True))

        snap = dict(doc)
        snap["natural_id"] = snap.pop("_id")
        snap["import_id"] = import_id
        snap["imported_at"] = now
        snap_docs.append(snap)

    db[collection].bulk_write(main_ops, ordered=False)
    db[snapshot_collection].insert_many(snap_docs, ordered=False)
    return len(docs)


def bulk_upsert_only(collection, docs, import_id=None):
    if not docs:
        return 0
    db = get_db()
    now = datetime.datetime.now()
    from pymongo import ReplaceOne

    ops = []
    for doc in docs:
        main = dict(doc)
        if import_id is not None:
            main["last_import_id"] = import_id
        main["last_imported_at"] = now
        ops.append(ReplaceOne({"_id": doc["_id"]}, main, upsert=True))
    db[collection].bulk_write(ops, ordered=False)
    return len(docs)